


Ninety Eight Percent

by Spoon888



Category: Transformers - All Media Types
Genre: Anal Sex, Attempted Abstinence, Bottom Megatron, Established Relationship, Homemade Contraceptives, Implied Mpreg, M/M, Sticky, Unsafe Sex
Language: English
Status: Completed
Published: 2018-04-07
Updated: 2018-04-18
Packaged: 2019-04-19 18:20:36
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 4,285
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14243088
Author URL: https://archiveofourown.org/users/Spoon888/pseuds/Spoon888
Summary: Lost in the unknown regions of space, running low on fuel and sanity, the unimaginable happens. The Nemesis runs out of contraceptives.





	1. Chapter 1

**Author's Note:**

> An excuse to write butt sex

"Okay," Skywarp appeared at their table, out of breath and mostly obscured behind the heaped pile of scrap in his arms. He released it and springs, plastic, tubes, screws and Primus knew what else spilled out amongst their evening refuel. "I'm onto something here."

Starscream pulled his cube away, worried Skywarp's mess would contaminate it. "And what would that be? A new hobby?"

"Not a hobby," Skywarp swung his legs over the bench and sat next to Thundercracker, smile wide. He picked up a pliable plastic bowl and brandished it at his trine. "A solution to our problem."

"What're you gonna do with that trash, Warp?" Thundercracker asked warily, eyeing the plastic.

"Not trash!" Skywarp announced, and snatched up the duct tape.

Glossa poking out of the side of his mouth as he concentrated, he spent the next five minutes hastily twisting, bending, and taping random pieces of plastic together. Starscream and Thundercracker exchanged increasingly concerned looks as he worked.

"There!" Skywarp slammed his creation down with conviction. And waited for his trine's praise.

"Oh," Starscream realised what it was. And instantly wished he hadn't. "It's a diaphragm."

And an ugly, misshapen one at that.

"No," Thundercracker stood up.

"But TC!" Skywarp picked up his creation and followed, "It'll work!"

"No!"

Starscream didn't blame him. There was no amount of pleasure in the universe was justification for sticking _that_ haphazard plastic thing up his valve. Even if it had been over a month since their stock of carrier inhibitors had run dry and Starscream was convinced his jaw would fall off if he had to give one more blow job, it still wasn't worth resorting to that.

And though his methods were disastrous, at least Skywarp was trying. Shockwave, their chief scientist, had condemned them all with his suggested solution. Abstinence.

If it didn't work for first year academy recruits, why would it work for a bored military faction with a penchant for breaking the rules?

"Screamer!" Skywarp came back to the table, waving at the fleeing Thundercracker, "Tell TC it'll work."

Starscream snatched the 'diaphragm' off him, pointing angrily. "Work?! It's split in the middle, idiot! Transfluid can navigate through it."

"So?"

Starscream was surprised his trine had lasted so long without sparking one another up with that sort of ignorance. It wasn't his responsibility to explain. He threw his servos up. "You are the _least_ qualified mech to be developing a contraceptive."

"Yeah well, what are _you_ doing? Where're those gestation blockers you were supposed to be making!"

"I don't have the materials available for that!" Starscream snarled. "We barely have the fuel spare to run the engines. I can't waste valuable resources on botched experiments just so you and the rest of these idiots can frag one another."

Skywarp picked up his diaphragm defensively, "It'll work and I'll prove it!"

He vanished in a huff, diaphragm and all.

Starscream chewed on his lip plate angrily, wanting to hit something. It was the only form of stress relief that _wouldn't_ result in accidental reproduction these days, and it wasn't half as satisfying.

 

* * *

 

Megatron nuzzled and kissed every inch of Starscream's armour he could reach, his cooling fans whirring like they were about to take off. Starscream felt his stiff spike bump the apex of his thighs again. He spread his legs encouragingly.

Megatron groaned, nose squashed into Starscream's neck, "You know we can't-"

"Just a little," Starscream pled, because he was _desperate_. It had been weeks since he'd felt Megatron inside him like that. He was sick of fingers and glossa and unsatisfying depth. "Just pull out before you finish."

Megatron snorted, but he was rocking against him, his spike nudging at the mesh of Starscream's bared valve. "Official protocol is abstinence."

Starscream rolled his optics. The entire ship was being subjected to that protocol and as members of high command, he and Megatron were expected to set a good example. Which didn't at all stop them from doing as they pleased behind closed doors.

"Yeah," Starscream breathed as a mouth kissed up his neck, "Because that worked well to prevent the six sparked mechs sat in your medbay."

Megatron huffed, breath wafting over Starscream's circuits, "It was five this morning..."

Starscream's lips curved, "Sunstorm."

Megatron extracted himself from Starscream's person to frown disapprovingly, "Blasted idiots. Turning my warship into a nursery-"

"Yes, because _you're_ so well behaved," Starscream squirmed under him, arching his back and thrusting his array in Megatron's direction.

"You're a tease," Megatron grumbled and began to rub the tip of his spike between Starscream's mesh lips, sending a shock of pleasure through Starscream's system every time he brushed that swollen sensor at the top. If only that feeling could be inside him. He seized Megatron by the hips and tried to urge him on.

Megatron groaned and stiffened. Starscream tilted his hips up expectantly, valve pulsing with want, drawn to the magnetic charge of Megatron's own erection.

"Right, that is it!" Megatron snapped, but instead of plugging in and shoving deep and filling Starscream till he was seeing the cosmos, Megatron flipped him. He fell onto his front.

"Aft up," Megatron ordered, hitching him up by the hips.

Starscream removed his face from Megatron's pillow, obeying eagerly, moving onto his knees.

Again he was surprised when a thumb pressed against the modesty panel over his exhaust, pushing it manually. Starscream jumped, leg flying back, almost kicking Megatron in the groin.

"Starscream!"

"What are you doing?!" Starscream tried to wriggle out of his grip, but Megatron was already spreading him open, thumb pressing into the tight ring of his port, testing it's pliability.

"Giving you the 'facing you've been asking for," Megatron answered simply, "Be still."

A heavy servo pressed down between Starscream's wings and pinned his front to the berth, curving his back strut. He huffed into the pillow, wings flicking in irritation. "This isn't exactly what I had in mind-"

Megatron paused, his weight still pressing down on Starscream from above, servo cupping his aft. "We can always return to our usual avenues?"

Starscream thought about his aching jaw and the click his right wrist had developed, and no, one more hand-job and he'd never shoot straight again. He wanted more. He wanted to give Megatron more, like he had _before_ the ship's cursed gyro malfunctioned and drove them through the wormhole that had gotten them lost for months now.

"You better not break anything," he relented.

Megatron laughed, and Starscream felt two fingers slide against his valve, gathering lubricant before trailing up to his port.

"You're asking me to be gentle?" Megatron pressed his finger in and twisted it, "Starscream, that's not like you."

"Be careful," Starscream corrected, still frowning at the foreign feel of Megatron stretching out a part of him that wasn't at all used to it. "Not gentle. There is a difference. If I have to visit the medbay and explain to Hook _why_ I can't walk or sit down, it'll be because you didn't know what you were do-ngh-!"

"I know exactly what I'm doing," Megatron announced pompously, shoving in two fingers without warning.

He scissored them before pulling away, then reached into the berthside drawer next to Starscream's helm. Megatron's servo banged against the sides as he searched for, and then drew out, a bottle of lubricant. The same Starscream squirrelled away for his... toys.

It was almost empty -yet another thing in desperate need of a restock- from it's very frequent use.

"You've been hitting this stuff pretty hard," Megatron observed, probably annoyed, as he emptied a glug over his spike and rubbed it in.

"What do you expect?" Starscream muttered, unperturbed.

Megatron didn't respond, emptying the rest of the lubricant down the cleft of Starscream's aft, smearing it in with fingers dipping past the stretched rim of his port. The tip of his spike came next, hot and zapping with charge. Just an inch or so south Starscream's lonely valve responded in kind.

A thumb spread him apart so there was just enough room for Megatron to shuffle in, grip himself firmly, and _push_. It wasn't the smooth glide of Megatron plugging into his valve. The head popped past the rim and Starscream tensed at the burn, and Megatron sunk no further.

Starscream shifted and tried to relax, but clenched down instead. Megatron huffed sharply, cursed, and then reached around for Starscream's valve, index finger slipping between mesh lips and swirling over the swollen anterior node with the expertise of someone who'd done it a thousand times before.

"That's it, there it is..." Megatron murmured as Starscream felt himself melt, tension draining away even as Megatron pushed onwards, splitting him open with a spike that had never felt quite _this_ big before.

"Hmm," he stifled a noise at the growing intensity, the different kind of fullness, moisture gathering in the corners of his optics, "Hng!"

"You're drooling on my pillow," Megatron teased, pausing two thirds in.

Starscream swallowed, "Just- get in!"

Megatron obeyed, and pulled Starscream all the way back until his aft tapped into Megatron's hips. The spike filled his port to such a capacity that Starscream could feel the fullness in his fuel tanks.

 _This_ is what he'd been missing.

"I've missed this," Megatron echoed the thought, relishing his hilt deep pleasure. He rocked appreciatively, "How does that feel?"

Starscream hid in Megatron's pillow and just hummed, processor blank of anything but foreign object detection warnings for his exhaust port. And _yes_ , he was aware there was something back there.

"Starscream?" Megatron rocked. And somehow it was more intense.

"Oh Primus!" Starscream hissed, throwing out a servo to catch the berth's headrest, gripping so tightly the metal beneath his digits bent. "Please..."

He didn't know what he was begging for. Mercy most likely. Pointless. Megatron was not a merciful mech. Nor did he have the patience to pace himself.

Megatron pulled out, devastatingly slow, waiting until just the tip was inside before sliding all the way back in.

"Mmph!" Starscream bit his lip to keep from crying out, but then Megatron started to thrust, tensing his abdominal armour and rolling his hips. Shallow and fast. Starscream's mouth hung open as he tried to catch his breath between his overwhelmed gasps.

He heard Megatron grunt and lean forwards, settling his weight over him. Starscream's legs buckled and he thumped into the berth as Megatron drilled him hard against the covers. The berth creaked with the increasing pace, barely audible over Starscream's matching cries. Huge servos gripped his aft and cleaved him open and yanked him up into ferociously driving thrusts, and with the last, the harshest, Megatron's spike twitched with a pulse, signalling the beginning of it's climax.

Starscream's valve tingled in response to the electronic pulse, the ghost of an overload.

Megatron groaned and thrust lazily, his transfluid emptying into Starscream's port and filling the little available space. It squelched wetly as Megatron rocked into the last twitches of his overload, spike already softening inside Starscream.

"Okay," Starscream breathed, voice rasping and cheeks wet from escaped tears. "You're done."

Megatron conceded with a grumble, pulling out and leaving Starscream spread and wet and uncomfortably loose. His exhaust didn't spring back like the flexible mesh of his valve. He felt the warmth of Megatron's overload escape and begin trickling out of him, cooling as it tracked down his thighs and the bud of his valve.

He felt Megatron's thumb smear the transfluid away. "It certainly knows where it wants to go." He commented.

"Hmm," Starscream agreed, and summoned the energy to roll onto his back. He stared hazily up at the very satisfied Megatron still observing his handy work, and planted a pede on his chest to nudge him away.

"My turn next," he mumbled.

"Your turn?" Megatron's optics brightened, then narrowed in irritation, "I wish you'd curb these wild ambitions of yours."

Which wasn't an explicit 'no', Starscream realised.

Megatron saw the curve of his lips and dropped down to him, mouth at his cockpit, kissing down. "Not today," he murmured against the glass. "Spread your legs..."

Starscream did so happily, ready for gentler pampering after his ordeal. His aft hurt, yes, but it was better than carrying...

And that was one thing he could be sure of. You couldn't get sparked via your exhaust.

 

* * *

 

When Megatron was summoned down to medbay he ran through his mental role call of who it could possibly be this time. A good third of the crew were now deemed 'unfit for duty' and within a few months they'd need to have a sizeable nursery set up for the fallout.

Megatron snorted angrily at the thought. The only free spaces were recreational. He wouldn't be able to go anywhere on the _Nemesis_ without hearing a sparkling _shriek_.

He entered into the medbay, explosive lecture at the ready, threats of chastity protocols prepared.

An exhausted looking medical team greeted him. Behind them stood Shockwave, and a furious looking Starscream.

"Shockwave?" Megatron said, surprised at his sub-commander. The irony of the one mech who'd actually suggested the abstinence pledge ending up sparked-

"I was called down to verify results after the vehement denial of the patient, my Lord," Shockwave inclined his helm respectfully. "You have been named the sire."

Megatron blinked at Shockwave's lone disappointed optic, and then flicked his gaze to the thunderous expression on Starscream's face behind him.

"Don't look so surprised, you Idiot!" Starscream burst out suddenly.

"What is the meaning of this?!" Megatron thundered back, looking between his lover and the gathered medical team. "Starscream, explain yourself!"

"What do you mean explain?!" Starscream yelled, "You were there!"

Megatron floundered. He hadn't been anywhere near Starscream's-

He thought back. Two weeks ago. Watching his transfluid trickle down Starscream's thighs pridefully, absently smearing away the drips spilling down his valve.

Oh _slag_. 

"... They certainly are determined, aren't they," He murmured, fury evaporating.

Starscream wasn't as accepting of the situation.

"You mean to tell me-!" He began yelling in front of everyone, "That all this time I've been taking it up my exhaust for nothing!?"

Reactions varied among their audience. Shockwave, though expressionless, managed to look horrified. Longhaul was nodding appreciatively. Megatron didn't know which was worst.

"Well, that's the whole elite trine down," Hook sighed, striking something off his datapad.

Megatron whipped back to him again, "What?!"

"Thundercracker and Skywarp," Hook shook his helm, "They thought they'd outsmarted their gestation protocols too."

His entire elite trine; out of commission. Starscream; sparked. Him; about to become a sire.

He needed a high-grade, but they'd run out of that weeks ago too.

"Well," he sighed, looking for the positives in this situation as he forced a reassuring smile Starscream's way, "You can't get anymore sparked than you already are."

Starscream struggled to keep his frown. Megatron could tell he was fighting back a smirk.

"... I suppose we'd better make the most of that." He said, mostly composed. 

Yes, Megatron intended to.

 


	2. Chapter 2

**Notes for the Chapter:**

> A few of you expressed an interest in seeing in a role reversal, so here's a second chapter.

Megatron couldn't recall having actually agreed to this. Starscream was vehement though. And he was also sparked. Megatron didn't have much hope of defending himself against such an aggressively, carrier-code addled seeker.

"I don't think you should be overextending yourself." Said Megatron diplomatically, in a last ditch attempt at saving himself.

Starscream's return expression could only be described as furious determination. Megatron didn't know how much of his anger was genuine, as opposed to just being a byproduct of one his now regular mood-swings. And though Megatron said 'regular mood-swing', he was also very aware that Starscream was the only sparked mech who'd had to have his nullrays confiscated as a result.

"Over extending myself?" Starscream hissed, loosing his temper straight off the bat. "The sparkling isn't even gestating yet. What the frag is there to _overextend_? And you weren't worried about _overextending_ me when you were fragging me last night! Or the night before! Or-!"

Megatron held up his servos, relenting before the seeker decided words weren't enough and flew across the room to attack him. Or worse, took up a _real_ pledge of abstinence for the duration of his carrying.

"Tonight then?" Megatron offered.

Starscream softened instantly, and it was notably more terrifying than the temper tantrum. He came closer, and Megatron took what little affection he could get from him. Starscream tucked himself close and Megatrom tolerated the seeker-typical nuzzling from Starscream, rolling his optics unseen.

"Is that a promise?"

Megatron thought about how his backup plan was to give Starscream an excessively long wing massage in hopes he fell asleep before, and nodded. "Of course."

He crossed his digits behind his back.

 

* * *

 

Megatron had developed an incredibly irritating habit of treating him like glass. Sparked or not, Starscream could still take the rougher touches -he craved them even. He didn't want adoring kisses and Megatron rubbing over his chest wistfully. He was still _Starscream_ , still a warrior, and he deserved to be 'faced like it. Not treated as little more than the precious frame carrying Lord Megatron's cherished offspring.

It was time to remind Megatron of such.

He struck as soon as they were alone, dragging Megatron from the desk and work he was quite obviously attempting to find refuge behind, his fingers tight around the broad wrist. He could feel Megatron trying to break his grasp, but he'd have to try harder to deter Starscream.

"Do you have no comprehension of patience?" Megatron groused, but let Starscream shove him onto the berth. He scooted back, knees apart, so Starscream had room to climb on with him. "Starscream, I have been thinking-"

"Oh, when aren't you thinking?" Starscream frowned at Megatron's 'trying to get out of trouble' voice. "Are we doing this or not?"

Conflict crossed Megatron's face, pride and self-preservation waring for dominance in his processor. Starscream ran his servos down his arms patiently, waiting for the answer.

Then Megatron kissed him, and he supposed that was his answer.

Megatron flopped back, the berth groaning and Starscream bouncing in his lap. Starscream climbed off his leader and hoisted his blocky aft up into his lap. Megatron planted his pedes on the berth and lifted his hips to help. Starscream kissed a knee, watching Megatron shuffle to make himself comfortable in such an unfamiliar position.

Megatron grunted, "Lubricant?"

Starscream had taken care of that earlier. Having exhausted his own supply he'd snuck into medical under the pretence of experiencing weird spark fluctuations. Hook had sneered at him like he thought he was panicked first-time parent, but as soon as his back was turned Starscream had swiped the bay's entire supply of medical lubricant.

He unsubspaced it and dangled it in Megatron's face.

A look of fear creased the old mech's brow.

"That is a lot of lubricant," he observed.

"It is," Starscream agreed, setting it aside for now. He took Megatron's knees and spread his thighs, exposing the triple set of panels hidden well with matte black paint. Starscream dragged a finger over their seams, playfully slow. First the spike panel (warm), then the valve (wet around the edges), and finally his exhaust.

The thighs framing his waist tensed with anticipation. Starscream grinned before moving up agains to rub a thumb against the codpiece hiding Megatron's spike.

It snapped back quickly, and Megatron exhaled sharply in surprise, his spike extending and filling until it was firm and thick in Starscream's palm. Starscream stroked it and leaned down to give it a kiss, a lick, just to get Megatron into the mood.

Megatron hummed happily, noticeability more relaxed. "We could do this instead?"

Starscream had spent the last _forever_ (or what felt like it at least) playing with Megatron's spike, and though it had never disappointed him in all that time, tonight was going to be different.

"No," he said, still working the spike to keep Megatron happy, but sliding his other servo further down to poke at that sealed aft port. "Open up."

With considerable discontented grumbling, Megatron exposed his exhaust to him. His valve cover slipped open as well, and Starscream cast it a curious look, wondering if Megatron hoped to distract him from his real goal here. He gave it a cursory touch anyway, fingers sliding through the damp folds.

"That won't work." He said, and snatched up the lubricant again.

He drowned Megatron's aft in it, letting it pool around his entrance and run down over Megatron's valve, some of it dripping down into Starscream's lap. He lathered his digits and pushed in.

Megatron huffed and stiffened like a big wuss. Starscream stopped, his first finger only half in, and sighed.

"I always knew you were a tight aft," he teased, considering the sincerity of Megatron's grimace.

Megatron response was to curse at him, which wasn't at all an acceptable way to speak to the mech carrying your sparkling. Starscream said as much, and shoved his digit in to the knuckle.

"Brat," Megatron hissed, instinctively trying to nudge Starscream away with a knee on his chest.

Starscream hushed him, tossing that same leg over his shoulder, ignoring the creak of old joints. The greater stretch made the angle easier and he moved to press in a second finger. Megatron made a noise of apprehension, and taking pity, Starscream entered him slowly.

Half the lubricant and another finger later, Megatron's spike was leaking transfluid across his own abdomen, a silver trail of it painted the grey of his armour. Despite his grumbling, they were getting somewhere.

Starscream released his own spike. He sighed in relief when it sprung out, straining with pressure and damp at the tip. Below, Megatron was eyeing it with some trepidation, undoubtably calculating in his own processor the size comparison between it, Starscream's fingers, and the looseness of his aft.

Starscream decided not to give him the time to worry himself over it.

He removed his fingers and lined up. Megatron, the fool, tensed immediately, so Starscream had to duck down and suck on his spike again, just long enough for the tension to drain away, for Megatron to hum happily. Starscream released the spike from with mouth with a wet pop and moved with the speed only a seeker could possess. 

Megatron's roar reverberated through the room, but it was indignant, rather than pained.

"You treacherous fiend!"

Well, maybe a little pained.

Starscream stayed where he was, sympathetic, rubbing up and down Megatron's trembling thighs. "Do you want me to take it out?"

Megatron breathed heavily, scowling at the ceiling. "No..."

Starscream patted him praisingly, "Do you want me to move?"

"Just... a moment..." Megatron said stiffly. Starscream could feel him flexing and clenching around him experimentally, wincing occasionally. He reached down and thumbed at the head of Megatron's spike, trying to take his mind off it.

It worked. Megatron unclenched enough that Starscream found himself getting dragged deeper. He whined, letting the natural suction of Megatron's aft take him in.

"Slow," Megatron groaned.

Starscream did, thrusting gently, shallowly at first. He watched the dimness of Megatron's optics fluctuate with every push, how his digits twitched where they clenched the sheets as they progressively bunched up under Megatron's back as Starscream rocked the berth.

Starscream was panting even before Megatron found the resilience to ask for more. Megatron urged him fiercely, his thighs clamping, hips bucking. Starscream threw his other leg over his shoulder and folded Megatron over to get as deep as he could, as hard as he could. His arms ached with the effort of having to support the larger frame. His pace faltered, his digits slipping on Megatron's armour.

"Foolish seeker," Megatron complained, and shifted out of his grip.

For one despairing moment, Starscream thought he'd blown his chance. But Megatron simply rose up, kissed him -wet and messy for Starscream's breathlessness- and readjusted himself in Starscream's lap, supporting his own weight on his knees.

Starscream leaned back and let him, gripping Megatron by the waist as the larger mech rode him, rearing up into those powerful thighs before dropping down and grinding Starscream's spike deep into himself.

Starscream could feel his own sparkbeat in his chest, quickening as his overload became imminent. He caught Megatron by the hips and halted him, holding him down, his spike buried as deep as it could go just in time for his overload to shoot out of him.

He made a strangled noise and shoved his face into Megatron's chest, wings jolting in time to the pulses of his emptying spike. For one joyous moment, his processor was completely blank of anything save Megatron, warm and strong and in his arms.

His unshuttered his optics.

His lap felt damp. He squinted up and Megatron was watching him with a raised brow, unimpressed. Starscream was too exhausted to suffer his reprimand though. He flopped back against the berth with a soft breath, barely shifting when he felt Megatron climb off him, his spent spike falling to the side.

After a quiet second he heard the huff of vents and the drag of armour on armour -Megatron fisting his own spike. He wasn't surprised a few moments later when hot strings of transfluid spilled across his cockpit.

He supposed he deserved that.

"I may have overextended myself..." He admitted quietly, his frame zapped of every last byte of energy. He needed a refuel, and a recharge. And a cloth.

A big servo cupped the side of his face, thumb stroking his cheek. "It's rather fortunate that I'm here to take care of you then, is it not?"

Starscream just nodded, and didn't even complain when Megatron pressed a kiss to his chest again, whispering an endearment to the undeveloped spark inside.

"Sap," he mumbled, and fell asleep to the sound of Megatron soft laugh.

 

 


End file.
